How to add a cell with Button? - iphone

Question

How would this work in this case? I created a NSMutabeArray *dataSource; in my .h file, but getting a bunch of errors:
"RootViewController.m: error: Semantic Issue: Property 'dataSource' not found on object of type 'RootViewController *'"
RootViewController.h
#import <UIKit/UIKit.h>
#interface RootViewController : UITableViewController {
NSMutableArray *dataSource;
}
#property (nonatomic,retain) NSMutableArray *dataSource;
- (IBAction)addButton:(id)sender;
#end
RootViewController.m
#import "RootViewController.h"
#implementation RootViewController
#synthesize dataSource;
- (void)viewDidLoad
{
[super viewDidLoad];
self.dataSource = [NSMutableArray arrayWithCapacity:1];
//adds right bar button.
UIBarButtonItem *addButton = [[UIBarButtonItem alloc]initWithBarButtonSystemItem:UIBarButtonSystemItemAdd target:self action:#selector(add:)];
self.navigationItem.rightBarButtonItem=addButton;
[addButton release];
}
-(void)addButton:(id)sender{
[self.dataSource addObject:#"New Item"];
NSIndexPath *newIndexPath = [NSIndexPath indexPathForRow:[self.dataSource count] inSection:0];
[self.dataSource insertRowsAtIndexPaths:[NSArray arrayWithObject:newIndexPath] withRowAnimation:UITableViewRowAnimationFade];
}

Answer 1

Some memory-guru will no doubt be able to tell you why #synthesize and mutable arrays and dictionaries (and sets, presumably) do not play well together. All I know is, initialize your mutable array explicitly and all will be well:
- (void)viewDidLoad
{
[super viewDidLoad];
self.dataSource = [NSMutableArray arrayWithCapacity:1];
//adds right bar button.
UIBarButtonItem *addButton = [[UIBarButtonItem alloc]initWithBarButtonSystemItem:UIBarButtonSystemItemAdd target:self action:#selector(add:)];
self.navigationItem.rightBarButtonItem=addButton;
[addButton release];
}
And, of course, release it in the dealloc.

Answer 2

You have not created property in .h file and you have used datasource variable with self.
please replace self.dataSource with dataSource or create property for it.
#property (nonatomic,retain) NSMutableArray *dataSource;
and synthesize in .m file
#synthesize dataSource;